class HashTable:
    def __init__(self, size=10):
        self.size = size
        self.table = [None] * size
    
    def _hash_function(self, value):
        # Simple hash function using ascii values
        return sum(ord(char) for char in value) % self.size

    def insert(self, value):
        index = self._hash_function(value)
        if self.table[index] is None:
            self.table[index] = value
    
    def __repr__(self):
        return str(self.table)

# Example usage
if __name__ == "__main__":
    ht = HashTable()
    print(ht._hash_function("apple"))
    ht.insert("apple")
    print(ht._hash_function("banana"))
    ht.insert("banana")
    print(ht._hash_function("orange"))
    ht.insert("orange")
    print(ht)